Lieb莫尔光子晶格及其光子学特性研究  

Lieb Moire Photonic Lattice and Its Photonic Properties

作　　者：张钰 高美妮 戴海涛 刘迎 吕且妮[2] ZHANG Yu;GAO Meini;DAI Haitao;LIU Ying;LÜQieni(Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology,School of Science,Tianjin University,Tianjin 300072,China;Key Laboratory of Opto-Electronics Information Technology,Ministry of Education,School of Precision Instrument&Optoelectronics Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学理学院天津市低维功能材料物理与制备技术重点实验室,天津300072 [2]天津大学精密仪器与光电子工程学院光电信息技术科学教育部重点实验室,天津300072

出　　处：《光子学报》2022年第6期214-221,共8页Acta Photonica Sinica

基　　金：国家自然科学基金(No.61975148)。

摘　　要：受到电子学领域双层扭曲石墨烯的启发,莫尔光子晶格的多种莫尔构型被证明具有光子局域等特性。将两个相同周期的Lieb子晶格旋转角36.87°叠加构造了Lieb莫尔晶格,并基于平面波展开法计算了其能带结构。结果表明,相比于常规的Lieb晶格,Lieb莫尔晶格的无量纲化光子禁带宽度最高可增加0.25,并且禁带中心发生了蓝移,因而更适合在光通信领域的应用。数值计算结果表明在Lieb莫尔晶格的能带结构中还具有平带,其特性可通过改变介质柱的几何参数进行调控,最高平整度可达到0.0018722。通过计算平整度最高时的电场分布,发现了局域的现象。基于Lieb晶格的莫尔构型可为光子晶体研究提供新的方法,也为研究复杂光子晶体结构提供新的平台。Inspired by the two-layer twisted graphene in electronics,Moire photonic lattices are also of great interest to researchers.Various Moire photonic configurations have been shown to possess peculiar photonic properties.In this paper,the photonic characteristics of Lieb Moire lattices composed of two overlapping Lieb sublattices with different rotation angles are studied.It is found that two Lieb sublattices can form a lattice with square characteristics when the rotation angle is 36.87°.Both the Lieb lattice and Lieb Moire lattice are composed of GaAs dielectric cylinders embedded in air.The radii of the cylinders of the two sublattices are r2 and r1 respectively.In order to compare their lattice properties,their lattice constants are set to be equal.With the same filling factor,the plane wave method is used to simulate the band structures of TM modes.According to numerical simulation,the Lieb Moire lattice has a wider photonic bandgap and a blueshift of the bandgap center than the conventional Lieb lattice,which is more suitable for optical communication applications.The main reason for the phenomenon is the change of dielectric contrast.To find the widest bandgaps,the filling factors of Lieb lattice and Lieb Moire lattice are further scanned,and the bandgap maps are obtained.The numerical simulation results show that the bandgap firstly increases and then decreases with the increasing filling factor,and the bandgap of Lieb Moire lattice is wider.At the same time,the photonic flat band properties are also observed.Three bands with very small gradients are observed in the band structure of Moire lattice,which are the 15th,22nd and 27th bands.In order to indicate the characteristics of flat bands,the flatness is defined as F.Through calculation,the 22th band has the minimum F,meaning it has the highest flatness.By changing the size of the dielectric cylinders,the flatness of the flat band can be higher.The flat band can lead to localization of field near lattice.By calculating the intensity of electric field distr

关 键 词：光子晶体 光子莫尔晶格 平面波展开法 禁带 电场局域 

分 类 号：O436[机械工程—光学工程] O438[理学—光学]